While some investigations have suggested that depression may lead to later unfavorable effects on heart rate variability, authors of a newly published study say they have found stronger evidence that the opposite is true.

Lower heart rate variability was independently associated with later increases in depressive symptoms, according to results of the longitudinal, twin difference study.

When researchers looked at the opposite direction, they found earlier depressive symptoms were associated with lower heart rate variability at follow-up in the study; however, investigators said those associations were not as robust and were largely explainable by antidepressant use.

That meant reduced heart rate variability is more likely a risk factor for depression, rather than a consequence, according to Minxuan Huang, ScM, of the department of epidemiology at Emory University Rollins School of Public Health, Atlanta, and his coinvestigators.

“These findings point to a central role of the autonomic nervous system in the regulation of mood and depression vulnerability,” they wrote in a report on the study appearing in JAMA Psychiatry.

The published analysis included 146 male twins, or 73 pairs, who participated in the national Vietnam Era Twin Registry.

Previous studies have linked depression to heart rate variability, a noninvasive index of cardiac autonomic nervous system regulation. However, these studies are not consistent on whether depression affects heart rate variability or vice versa, and the studies have been limited in their ability to assess the relationship between those two variables over time, the investigators said.